1. Field of the Invention
This invention relates generally to the production of slide fasteners having coupling or mating elements made of a thermoplastic material, and more particularly to a method for supplying such a plastic material to a molding machine for molding the same into a desired formation on a pair of stringer tapes.
2. Prior Art
Slide fastener coupling elements of a discrete formation are provided on a pair of stringer tapes most commonly by means of injection-molding, in which instance runners, sprues and other debris of the element-forming plastic material are encountered that are to be removed from the slide fastener chain.
It has long since been desired to make use of such runners and sprues for replenishment of a supply of starting plastic materials which are versatile in color.
However, difficulty has been experienced in obtaining homogeneous color distribution of the fastener elements on the stringer tapes due to thermal decomposition, pollution or moisture absorption of the used runners and sprues.